An externality is defined as a benefit or cost that is imposed on a third party, such as society, other than the producer or consumer of a good or service, or, more simply, an economic side effect.
The bacteria is a thermophile and is widely distributed in soil, hot springs, ocean sediment, and is a cause of spoilage in food products. It will grow within a temperature range of 30-75 degrees Celsius. Some strains are capable of oxidizing carbon monoxide aerobically.iological indicators are used in conjunction with chemical indicators and process indicators to validate sterilization processes. It was first described in 1920 as Bacillus stearothermophilus, but, together with Bacillus thermoglucosidasius, it was reclassified as a member of the genus Geobacillus in 2001.
Photo: Pete Wardell/ CDC. The Citrobacter species, including Citrobacter freundii, are aerobic gram-negative bacilli. Citrobacter freundii are long rod-shaped bacteria typically 1-5 Î¼m in length [1]. Most C. freundii cells are surrounded by many flagella used to move about, but a few are non-motile.cology. Citrobacter freundii are commonly found in the environment, mainly in soil, water, and sewages. They are an indicator of potential contamination of water. They are also found on different organs of diseased animals, including mammals, birds, reptiles, and amphibians [1].